This study evaluated the feasibility of using occipitoparietal alpha activity to drive target/non-target classification in a brain-computer interface for communication. EEG data were collected from 12 participants who completed BCI Rapid Serial Visual Presentation calibrations at two different presentation rates: 1 and 4 Hz. Attention-related changes in posterior alpha activity were compared to two event-related potentials : N200 and P300. Machine learning approaches evaluated target/non-target classification accuracy using alpha activity. Results indicated significant alpha attenuation following (...) target letters at both 1 and 4 Hz presentation rates, though this effect was significantly reduced in the 4 Hz condition. Target-related alpha attenuation was not correlated with coincident N200 or P300 target effects. Classification using posterior alpha activity was above chance and benefitted from individualized tuning procedures. These findings suggest that target-related posterior alpha attenuation is detectable in a BCI RSVP calibration and that this signal could be leveraged in machine learning algorithms used for RSVP or comparable attention-based BCI paradigms. (shrink)

Attentional biases have received considerable focus in research on cognitive biases and body dissatisfaction (BD). However, most work has focused on spatial allocation of attention. The current two experiments employed a rapid serial visual presentation (RSVP) task to investigate the temporal allocation of attention to body-related words among young females with high and low BD. Experiment 1 assessed the stimulus-driven attention of body-related stimuli. Participants identified a neutral second target (T2) as accurately as possible while ignoring (...) the preceding neutral, fat-, or thin-related first target (T1). As expected, we observed spontaneous attentional blink effects elicited by fat- and thin-related T1s among participants with high BD, suggesting enhanced awareness of body-related stimuli even when this information does not have to be identified. Such effects did not emerge among participants without BD. Experimental 2 investigated the goal-directed attention of body-related stimuli, during which participants needed to identify both the T1 and neutral T2. Participants with BD showed reduced attentional blink effects after both fat- and thin-related T1, suggesting facilitated consolidation of body-related information in goal-directed attention among participants with BD. The findings may have important clinical implications for understanding how to decrease and even prevent body image dissatisfaction. (shrink)

Our research aimed to investigate the effectiveness of auditory, visual, and audiovisual warning signals for capturing the attention of the pilot, and how stimulus onset asynchronies in audiovisual stimuli affect pilots perceiving the bimodal warning signals under different perceptual load conditions. In experiment 1 of the low perceptual load condition, participants discriminated the location of visual targets preceded by five different types of warning signals. In experiment 2 of high perceptual load, participants completed the location task identical to (...) a low load condition and a digit detection task in a rapid serial visual presentation stream. The main effect of warning signals in two experiments showed that visual and auditory cues presented simultaneously could effectively and efficiently arouse the attention of the pilots in high and low load conditions. Specifically, auditory, AV, and visual preceding auditory stimulus by 100 ms increased the spatial orientation to a valid position in low load conditions. With the increase in visual perceptual load, auditory preceding the visual stimulus by 100 ms and A warning signals had stronger spatial orientation. The results are expected to theoretically support the optimization design of the cockpit display interface, contributing to immediate flight crew awareness. (shrink)

Three experiments investigated the role of target-target perceptual similarity within the attentional blink. Various geometric shapes were presented in a rapid serial visual presentation task. Targets could have 2, 1, or 0 shared features. Features included shape and size. The second target was presented after five or six different lags after the first target. The task was to detect both targets on each trial. Second-target report accuracy was increased by target-target similarity. This modulation was observed more (...) for mixed-trial design as compared with blocked design. Results are discussed in terms of increased stability of working memory representations and reduced interference for second-target processing. (shrink)

Previous research has shown that the proactive deprioritization of emotional distractors through the provision of information about the distractors or passive habituation of emotional distractors may attenuate emotion-induced blindness (EIB) in the rapid serial visual presentation stream. However, whether prior memory encoding of emotional distractors could bias the EIB effect remains unknown. To address this question, this study employed a three-phase paradigm integrating an item-method direct forgetting (DF) procedure with a classic EIB procedure. Participants completed a (...) memory coding phase to either remember or forget negative pictures, then performed an intermediate phase of the EIB test, and finally finished a recognition test. Critically, the same to-be-forgotten (TBF) and to-be-remembered (TBR) negative pictures in the memory learning phase were used as emotional distractors in the intermediate EIB test. The results replicated the typical DF effect by showing higher recognition accuracies for TBR pictures compared to those for TBF pictures. More importantly, the TBF negative distractors attenuated the EIB effect compared to the TBR negative distractors, but showed a comparable EIB effect as the novel negative distractors. These findings indicate that prior memory encoding manipulations of negative distractors could bias subsequent EIB effects, providing an important approach to modulate the EIB effect. (shrink)

ABSTRACTThe attentional blink is the impaired ability to detect a second target when it follows shortly after the first among distractors in a rapid serial visual presentation...

A quintessential challenge for any perceptual system is the need to focus on task-relevant information without being blindsided by unexpected, yet important information. The human visual system incorporates several solutions to this challenge, one of which is a reflexive covert attention system that is rapidly responsive to both the physical salience and the task-relevance of new information. This paper presents a model that simulates behavioral and neural correlates of reflexive attention as the product of brief neural attractor states that (...) are formed across the visual hierarchy when attention is engaged. Such attractors emerge from an attentional gradient distributed over a population of topographically organized neurons and serve to focus processing at one or more locations in the visual field, while inhibiting the processing of lower priority information. The model moves towards a resolution of key debates about the nature of reflexive attention, such as whether it is parallel or serial, and whether suppression effects are distributed in a spatial surround, or selectively at the location of distractors. Most importantly, the model develops a framework for understanding the neural mechanisms of visual attention as a spatiotopic decision process within a hierarchy and links them to observable correlates such as accuracy, reaction time, and the N2pc and PD components of the EEG. This last contribution is the most crucial for repairing the disconnect that exists between our understanding of behavioral and neural correlates of attention. (shrink)

Humans have been shown capable of performing many cognitive tasks using information of which they are not consciously aware. This raises questions about what role consciousness actually plays in cognition. Here, we explored whether participants can learn cue-target contingencies in an attentional learning task when the cues were presented below the level of conscious awareness, and how this differs from learning about conscious cues. Participants’ manual (Experiment 1) and saccadic (Experiment 2) response speeds were influenced by both conscious and unconscious (...) cues. However, participants were only able to adapt to reversals of the cue-target contingencies (Experiment 1) or changes in the reliability of the cues (Experiment 2) when consciously aware of the cues. Therefore, although visual cues can be processed unconsciously, learning about cues over a few trials requires conscious awareness of them. Finally, we discuss implications for cognitive theories of consciousness. (shrink)

Decision making in any brain is imperfect and costly in terms of time and energy. Operating under such constraints, an organism could be in a position to improve performance if an opportunity arose to exploit informative patterns in the environment being searched. Such an improvement of performance could entail both faster and more accurate (i.e., reward-maximizing) decisions. The present study investigated the extent to which human participants could learn to take advantage of immediate patterns in the spatial arrangement of serially (...) presented foods such that a region of space would consistently be associated with greater subjective value. Eye movements leading up to choices demonstrated rapidly induced biases in the selective allocation of visual fixation and attention that were accompanied by both faster and more accurate choices of desired goods as implicit learning occurred. However, for the control condition with its spatially balanced reward environment, these subjects exhibited preexisting lateralized biases for eye and hand movements (i.e., leftward and rightward, respectively) that could act in opposition not only to each other but also to the orienting biases elicited by the experimental manipulation, producing an asymmetry between the left and right hemifields with respect to performance. Potentially owing at least in part to learned cultural conventions (e.g., reading from left to right), the findings herein particularly revealed an intrinsic leftward bias underlying initial saccades in the midst of more immediate feedback-directed processes for which spatial biases can be learned flexibly to optimize oculomotor and manual control in value-based decision making. The present study thus replicates general findings of learned attentional biases in a novel context with inherently rewarding stimuli and goes on to further elucidate the interactions between endogenous and exogenous biases. (shrink)

Previous studies of verbal short-term memory indicate that STM for serial order may be linked to language development and developmental language disorder. To clarify whether a domain-general mechanism is impaired in DLD, we studied the relations between age, non-verbal serial STM, and language competence. We hypothesized that non-verbal serial STM differences between groups of children with DLD and typically developing children are linked to their language acquisition differences. Fifty-one children with DLD and sixty-six TD children participated as (...) part of the HelSLI project in this cross-sectional study. The children were 4–6-year-old monolingual native Finnish speakers. They completed several tests of language and cognitive functioning, as well as new game-like tests of visual and auditory non-verbal serial STM. We used regression analyses to examine how serial STM moderates the effect of age on language. A non-verbal composite measure of serial visual and auditory STM moderated cross-sectional development of receptive language in the children with DLD. This moderation was not observed in the TD children. However, we found more rapid cross-sectional development of non-verbal serial STM in the TD children than in the children with DLD. The results suggest that children with DLD may be more likely to have compromised general serial STM processing and that superior non-verbal serial STM may be associated with better language acquisition in children with DLD. (shrink)

This study investigates the influence of contrastive stress on the on-line interpretation of ambiguous spoken sentences containing the focus operator only. The pattern of phonological stress was manipulated so as to associate different linguistic expressions with the focus operator only and to invoke different interpretations. Sentences with marked and neutral stress were evaluated relative to visually presented scenes, which depicted a situation consistent with alternative interpretations. Using a head-mounted eye-movement recording system, we measured the processing difficulty associated with phonological stress (...) and subjects’ fixation duration on the various objects in the scenes. Not only was response accuracy superior on sentences with marked stress, as compared to ones with neutral stress, the pattern of fixations revealed earlier resolution of ambiguity in the marked stress condition. The findings suggest that the parser computes multiple interpretations of ambiguous sentences on-line, with marked stress assisting in the rapid resolution of semantic ambiguity. (shrink)

The construction of complex simulation models and the application of new computer hardware to ecological problems has resulted in the need for many ecologists to rely on computer programmers to develop their modelling software. However, this can lead to a lack of flexibility and understanding in model implementation and in resource problems for researchers. This paper presents a new programming language, Viola, based on a simple organisational concept which can be used by most researchers to develop complex simulations much more (...) easily than could be achieved with standard programming languages such as C++. The language is object oriented and implemented through a visual interface. It is specifically designed to cope with complicated individual based behavioural simulations and comes with embedded concurrency handling abilities. (shrink)

Perception is a first-person internal sensation induced within the nervous system at the time of arrival of sensory stimuli from objects in the environment. Lack of access to the first-person properties has limited viewing perception as an emergent property and it is currently being studied using third-person observed findings from various levels. One feasible approach to understand its mechanism is to build a hypothesis for the specific conditions and required circuit features of the nodal points where the mechanistic operation of (...) perception take place for one type of sensation in one species and to verify it for the presence of comparable circuit properties for perceiving a different sensation in a different species. The present work explains visual perception in mammalian nervous system from a first-person frame of reference and provides explanations for the homogeneity of perception of visual stimuli above flicker fusion frequency, the perception of objects at locations different from their actual position, the smooth pursuit and saccadic eye movements, the perception of object borders, and perception of pressure phosphenes. Using results from temporal resolution studies and the known details of visual cortical circuitry, explanations are provided for (a) the perception of rapidly changing visual stimuli, (b) how the perception of objects occurs in the correct orientation even though, according to the third-person view, activity from the visual stimulus reaches the cortices in an inverted manner and (c) the functional significance of well-conserved columnar organization of the visual cortex. A comparable circuitry detected in a different nervous system in a remote species-the olfactory circuitry of the fruit fly Drosophila melanogaster-provides an opportunity to explore circuit functions using genetic manipulations, which, along with high-resolution microscopic techniques and lipid membrane interaction studies, will be able to verify the structure-function details of the presented mechanism of perception. (shrink)

In the contextual cueing task, visual search is faster for targets embedded in invariant displays compared to targets found in variant displays. However, it has been repeatedly shown that participants do not learn repeated contexts when these are irrelevant to the task. One potential explanation lays in the idea of associative blocking, where salient cues block the learning of invariant associations in the task-irrelevant subset of items. An alternative explanation is that the associative blocking rather hinders the allocation of (...) attention to task-irrelevant subsets, but not the learning per se. The current work examined these two explanations. In two experiments, participants performed a visual search task under a rapid presentation condition in Experiment 1, or under a longer presentation condition in Experiment 2. In both experiments, the search items within both old and new displays were presented in two colors which defined the irrelevant and task-relevant items within each display. The participants were asked to search for the target in the relevant subset in the learning phase. In the transfer phase, the instructions were reversed and task-irrelevant items became task-relevant. In line with previous studies, the search of task-irrelevant subsets resulted in no cueing effect post-transfer in the longer presentation condition; however, a reliable cueing effect was generated by task-irrelevant subsets learned under the rapid presentation. These results demonstrate that under rapid display presentation, global attentional selection leads to global context learning. However, under a longer display presentation, global attention is blocked, leading to the exclusive learning of invariant relevant items in the learning session. (shrink)

Experiments are presented showing that visual search for Mueller-Lyer (ML) stimuli is based on complete configurations, rather than component segments. Segments easily detected in isolation were difficult to detect when embedded in a configuration, indicating preemption by low-level groups. This preemption—which caused stimulus components to become inaccessible to rapid search—was an all-or-nothing effect, and so could serve as a powerful test of grouping. It is shown that these effects are unlikely to be due to blurring by simple spatial (...) filters at early visual levels. It is proposed instead that they are due to more sophisticated processes that rapidly bind contour fragments into spatially-extended assemblies. These results support the view that rapid visual search cannot access the primitives formed at the earliest stages of visual processing; rather, it can access only higher-level, more ecologically-relevant structures. (shrink)

Some things look more complex than others. For example, a crenulate and richly organized leaf may seem more complex than a plain stone. What is the nature of this experience—and why do we have it in the first place? Here, we explore how object complexity serves as an efficiently extracted visual signal that the object merits further exploration. We algorithmically generated a library of geometric shapes and determined their complexity by computing the cumulative surprisal of their internal skeletons—essentially quantifying (...) the “amount of information” within each shape—and then used this approach to ask new questions about the perception of complexity. Experiments 1–3 asked what kind of mental process extracts visual complexity: a slow, deliberate, reflective process (as when we decide that an object is expensive or popular) or a fast, effortless, and automatic process (as when we see that an object is big or blue)? We placed simple and complex objects in visual search arrays and discovered that complex objects were easier to find among simple distractors than simple objects are among complex distractors—a classic search asymmetry indicating that complexity is prioritized in visual processing. Next, we explored the function of complexity: Why do we represent object complexity in the first place? Experiments 4–5 asked subjects to study serially presented objects in a self‐paced manner (for a later memory test); subjects dwelled longer on complex objects than simple objects—even when object shape was completely task‐irrelevant—suggesting a connection between visual complexity and exploratory engagement. Finally, Experiment 6 connected these implicit measures of complexity to explicit judgments. Collectively, these findings suggest that visual complexity is extracted efficiently and automatically, and even arouses a kind of “perceptual curiosity” about objects that encourages subsequent attentional engagement. (shrink)

Quality of language comprehension determines performance in all kinds of activities including academics. Processing of words initially develops as auditory, and gradually extends to visual as children learn to read. School failure is highly related to listening and reading comprehension problems. In this study we analyzed sex-differences in comprehension of texts in Spanish in three modalities presented to 12–14-years old students, native in Spanish. We controlled relevant cognitive variables such as attention, phonological and semantic fluency and speed of processing. (...) Girls’ comprehension was similar in the three modalities of presentation, however boys were importantly benefited by dual-modality as compared to boys exposed only to visual or auditory text presentation. With respect to the relation of text comprehension and school performance, students with low grades in Spanish showed low auditory comprehension. Interestingly, visual and dual modalities preserved comprehension levels in these low skilled students. Our results suggest that the use of visual-text support during auditory language presentation could be beneficial for low school performance students, especially boys, and encourage future research to evaluate the implementation in classes of the rapidly developing technology of simultaneous speech transcription, that could be, in addition, beneficial to non-native students, especially those recently incorporated into school or newly arrived in a country from abroad. (shrink)

Contribution of emotional valence and arousal to attentional processing over time is not fully understood. We employed a rapid serial visual paradigm in three experiments to investigate the...

The task of visual search is to determine as rapidly as possible whether a target item is present or absent in a display. Rapidly detected items are thought to contain features that correspond to primitive elements in the human visual system. In previous theories, it has been assumed that visual search is based on simple two-dimensional features in the image. However, visual search also has access to another level of representation, one that describes properties in the (...) corresponding three-dimensional scene. Among these properties are three dimensionality and the direction of lighting, but not viewing direction. These findings imply that the parallel processes of early vision are much more sophisticated than previously assumed. (shrink)

This chapter presents findings on a study of neuropsychological aspects of visual hallucinations with a focus on hallucinations in Parkinson's disease. The results of the study suggest that VHs in PD are a complex multifactor effect of different risk factors, primarily the dysfunctions of the visual system and the system that regulates rapid eye movement sleep and arousal. The study reported here also investigated whether the same risk factors are implicated in proneness to VHs as they are (...) in VHs in PD. The results suggest that the predisposition to VHs in the healthy young population is a multifactor effect of strikingly similar risk factors to those found in PD. However, in addition to the dysfunctions of the visual and arousal system, proneness to hallucinations in the normal population is also predicted by a specific personality profile. (shrink)

An incoherent visualization is when aspects of different senses of a word are present in the same visualization. We describe and implement a new model of creating contextual coherence in the visual imagination called Coherencer, based on the SOILIE model of imagination. We show that Coherencer is able to generate scene descriptions that are more coherent than SOILIE's original approach as well as a parallel connectionist algorithm that is considered competitive in the literature on general coherence. We also show (...) that co-occurrence probabilities are a better association representation than holographic vectors and that better models of coherence improve the resulting output independent of the association type that is used. Theoretically, we show that Coherencer is consistent with other models of cognitive generation. In particular, Coherencer is a similar, but more cognitively plausible model than the C3 model of concept combination created by Costello and Keane. We show that Coherencer is also consistent with both the modal schematic indices of perceptual symbol systems theory and the amodal contextual constraints of Thagard's theory of coherence. Finally, we describe how Coherencer is consistent with contemporary research on the hippocampus, and we show evidence that the process of making a visualization coherent is serial. (shrink)

Popular movies present chunk-like events that promote episodic, serial updating of viewers’ representations of the ongoing narrative. Event-indexing theory would suggest that the beginnings of new scenes trigger these updates, which in turn require more cognitive processing. Typically, a new movie event is signaled by an establishing shot, one providing more background information and a longer look than the average shot. Our analysis of 24 films reconfirms this. More important, we show that, when returning to a previously shown location, (...) the re-establishing shot reduces both context and duration while remaining greater than the average shot. In general, location shifts dominate character and time shifts in event segmentation of movies. In addition, over the last 70 years re-establishing shots have become more like the noninitial shots of a scene. Establishing shots have also approached noninitial shot scales, but not their durations. Such results suggest that film form is evolving, perhaps to suit more rapid encoding of narrative events. (shrink)

The present study combined magnetoencephalography recordings with fast periodic visual stimulation to investigate automatic neural responses to morphemes in developing and skilled readers. Native English-speaking children and adults were presented with rapid streams of base stimuli interleaved periodically with oddballs. In a manipulation-check condition, tapping into word recognition, oddballs featured familiar words embedded in a stream of consonant strings. In the experimental conditions, the contrast between oddball and base stimuli was manipulated in order to probe selective stem and (...) suffix identification in morphologically structured pseudowords. Neural responses at the oddball frequency and harmonics were analyzed at the sensor level using non-parametric cluster-based permutation tests. As expected, results in the manipulation-check condition revealed a word-selective response reflected by a predominantly left-lateralized cluster that emerged over temporal, parietal, and occipital sensors in both children and adults. However, across the experimental conditions, results yielded a differential pattern of oddball responses in developing and skilled readers. Children displayed a significant response that emerged in a mostly central occipital cluster for the condition tracking stem identification in the presence of suffixes. In contrast, adult participants showed a significant response that emerged in a cluster located in central and left occipital sensors for the condition tracking suffix identification in the presence of stems. The present results suggest that while the morpheme identification system in Grade 5–6 children is not yet adult-like, it is sufficiently mature to automatically analyze the morphemic structure of novel letter strings. These findings are discussed in the context of theoretical accounts of morphological processing across reading development. (shrink)

Reading numbers aloud involves visual processes that analyze the digit string and verbal processes that produce the number words. Cognitive models of number reading assume that information flows from the visual input to the verbal production processes—a feed‐forward processing mode in which the verbal production depends on the visual input but not vice versa. Here, I show that information flows also in the opposite direction, from verbal production to the visual input processes. Participants read aloud briefly (...) presented multi‐digit strings in Hebrew, in which the order of words is congruent with the order of digits (21 = twenty‐and‐one), and in Arabic, in which the ones word precedes the tens word (one‐and‐twenty). The error‐by‐digit‐position curve was affected by language: relative to Hebrew, in Arabic the error rate was slightly lower for the unit digit and slightly higher for the decade digit, indicating that in Arabic the unit digit was processed earlier and the decade digit later, in accord with the Arabic word order. This language‐dependent processing order originated in the visual level and was not a verbal confound, because it persisted even when I controlled for the serial position of the decade/unit word in the verbal number by using numbers with 0 (two hundred three/two hundred thirty). I conclude that the visual analyzer's digit scanning order, decade‐first or unit‐first, is not fixed but affected by the language in which the number is produced—a top‐down, verbal‐to‐visual information flow. (shrink)

Visual attention evolved as an adaptive mechanism allowing us to cope with a rapidly changing environment. It enables the facilitated processing of relevant information, often automatically and governed by implicit motives. However, despite recent advances in understanding the relationship between consciousness and visual attention, the functional scope of unconscious attentional control is still under debate. Here, we present a novel masking paradigm in which volunteers were to distinguish between varying orientations of a briefly presented, masked grating stimulus. Combining (...) signal detection theory and subjective measures of awareness, we show that performance on unaware trials was consistent with visual selection being weighted towards repeated orientations of Gabor patches and reallocated in response to a novel unconsciously processed orientation. This was particularly present in trials in which the prior feature was strongly weighted and only if the novel feature was invisible. Thus, our results provide evidence that invisible orientation stimuli can trigger the reallocation of history-guided visual selection weights. (shrink)

The human sentence processor is able to make rapid predictions about upcoming linguistic input. For example, upon hearing the verb eat, anticipatory eye-movements are launched toward edible objects in a visual scene. However, the cognitive mechanisms that underlie anticipation remain to be elucidated in ecologically valid contexts. Previous research has, in fact, mainly used clip-art scenes and object arrays, raising the possibility that anticipatory eye-movements are limited to displays containing a small number of objects in a visually impoverished (...) context. In Experiment 1, we confirm that anticipation effects occur in real-world scenes and investigate the mechanisms that underlie such anticipation. In particular, we demonstrate that real-world scenes provide contextual information that anticipation can draw on: When the target object is not present in the scene, participants infer and fixate regions that are contextually appropriate. Experiment 2 investigates whether such contextual inference requires the co-presence of the scene, or whether memory representations can be utilized instead. The same real-world scenes as in Experiment 1 are presented to participants, but the scene disappears before the sentence is heard. We find that anticipation occurs even when the screen is blank, including when contextual inference is required. We conclude that anticipatory language processing is able to draw upon global scene representations to make contextual inferences. These findings are compatible with theories assuming contextual guidance, but posit a challenge for theories assuming object-based visual indices. (shrink)

Participants who were unable to detect familiarity from masked 17 ms faces did report a vague, partial visual percept. Two experiments investigated the relative strength of the visual percept generated by famous and unfamiliar faces, using masked 17 ms exposure. Each trial presented simultaneously a famous and an unfamiliar face, one face in LVF and the other in RVF. In one task, participants responded according to which of the faces generated the stronger visual percept, and in the (...) other task, they attempted an explicit familiarity decision. The relative strength of the visual percept of the famous face compared to the unfamiliar face was moderated by response latency and participants’ attitude towards the famous person. There was also an interaction of visual field with response latency, suggesting that the right hemisphere can generate a visual percept differentiating famous from unfamiliar faces more rapidly than the left hemisphere. Participants were at chance in the explicit familiarity decision, confirming the absence of awareness of facial familiarity. (shrink)

Sequence learning is fundamental to a wide range of cognitive functions. Explaining how sequences—and the relations between the elements they comprise—are learned is a fundamental challenge to cognitive science. However, although hundreds of articles addressing this question are published each year, the actual learning mechanisms involved in the learning of sequences are rarely investigated. We present three experiments that seek to examine these mechanisms during a typing task. Experiments 1 and 2 tested learning during typing single letters on each trial. (...) Experiment 3 tested for “chunking” of these letters into “words.” The results of these experiments were used to examine the mechanisms that could best account for them, with a focus on two particular proposals: statistical transitional probability learning and discriminative error-driven learning. Experiments 1 and 2 showed that error-driven learning was a better predictor of response latencies than either n-gram frequencies or transitional probabilities. No evidence for chunking was found in Experiment 3, probably due to interspersing visual cues with the motor response. In addition, learning occurred across a greater distance in Experiment 1 than Experiment 2, suggesting that the greater predictability that comes with increased structure leads to greater learnability. These results shed new light on the mechanism responsible for sequence learning. Despite the widely held assumption that transitional probability learning is essential to this process, the present results suggest instead that the sequences are learned through a process of discriminative learning, involving prediction and feedback from prediction error. (shrink)

In some cases our sensory organs are no longer capable of rendering processes in the external world perceptible to us. Their inadequacy expresses itself, for example, in phenomena that involve the kind of expansion of space and time in which the conditions for summary perception are no longer at all present. The resources that aid our immediate sense perception in these circumstances will thus be charged with the task of expanding or diminishing space and time to the extent that the (...) contiguity and succession of events is comprehensible to us. The microscope is thus essentially based upon the principle of spatial expansion, the map on that of spatial diminution. The pertinent contrivances for these purposes are largely derived from the graphic arts. How stereoscopy and instantaneous photography, which is based on temporal expansion, facilitate our perception! In spite of the multifarious applications of photography, one has yet to take the step of employing it in the opposite direction, namely as a means of temporal diminution. We demonstrate that phenomena that take place in too ephemeral and too rapid a succession for our eyes can, with the help of instantaneous photographs in series, be analyzed with our senses as the event passes in a comparatively longer time. Quite analogously, we could also compress into a small duration the moments of an event separated widely from one another in time and thereby give our perception an understanding of the nature thereof. (shrink)

Recent decades have witnessed the rapid evolution of robotic applications and their expansion into a variety of spheres with remarkable achievements. This article researches a crucial technique of robot manipulators referred to as visual servoing, which relies on the visual feedback to respond to the external information. In this regard, the visual servoing issue is tactfully transformed into a quadratic programming problem with equality and inequality constraints. Differing from the traditional methods, a gradient-based recurrent neural network (...) for solving the visual servoing issue is newly proposed in this article in the light of the gradient descent method. Then, the stability proof is presented in theory with the pixel error convergent exponentially to zero. Specifically speaking, the proposed method is able to impel the manipulator to approach the desired static point while maintaining physical constraints considered. After that, the feasibility and superiority of the proposed GRNN are verified by simulative experiments. Significantly, the proposed visual servo method can be leveraged to medical robots and rehabilitation robots to further assist doctors in treating patients remotely. (shrink)

Ageing is associated with declines in several cognitive abilities including working memory. The goal of the present study was to assess whether emotional information could reduce the age gap in the quantity and quality of representations in visual WM. Young and older adults completed a serial image recognition task and a colour-image binding task. Results of the SIR task showed worse performance for negative than neutral and positive images within the older group, hence enlarging the age gap in (...) WM. In the CIB task, recall precision was lower in the old than young adults, showing an ageing decline in the quality of WM representations. Positive images tended to improve precision, but this boost was similar for both age groups. In sum, emotional content did not reduce the age gap in visual WM. (shrink)

Mechanisms of selective attention exert a powerful influence on visual perception. We examined whether attentional selection is necessary for generation of the vivid colours experienced by individuals with grapheme-colour synaesthesia. Twelve synaesthetes and matched controls viewed rapid serial displays of nonsense characters within which were embedded an oriented grating (T1) and a letter-prime (T2), forming a modified attentional blink (AB) task. At the end of the stream a coloured probe appeared that was either congruent or incongruent with (...) the synaesthetic colour elicited by the letter-prime. When the prime was attended, synaesthetes showed a reliable effect of prime-probe congruency. In contrast, when the prime appeared at 350 ms following T1 (during the AB), the congruency effect was eliminated. Our findings suggest that focused attention is crucial for inducing letters to elicit colours in synaesthesia. © 2009 Elsevier B.V. All rights reserved. (shrink)

The global precedence effect, originally referring to processing hierarchical visual stimuli composed of letters, is characterised by both global advantage and global interference. We present herein a study of how this effect is modulated by the variables letter and sex. The Navon task, using the letters “H” and “S,” was administered to 78 males and 168 females. No interaction occurred between the letter and sex variables, but significant main effects arose from each of these. Reaction times revealed that the (...) letter “H” was identified more rapidly in the congruent condition both in the global and the local task, and the letter “S” in the incongruent condition for the local task. Also, although RTs showed a GPE in both males and females, males displayed shorter reaction times in both global and local tasks. Furthermore, luteal women showed higher d’ index in the congruent condition for the local task than both follicular women and hormonal contraceptive users, as well as longer exploration time of the irrelevant level during the global task than males. We conclude that, according to the linear periodicity law, the GPE is enhanced for compound letters with straight vs. curved strokes, whereas it is stronger in males than in females. Relevantly, luteal phase of the menstrual cycle seems to tilt women to rely on finer grained information, thus exhibiting an analytical processing style in global/local visual processing. (shrink)

Recent advances in our understanding of visual perception have shown it to be a far more complex and counterintuitive process than previously believed. Several important consequences follow from this. First, the design of an effective statistical graphics system is unlikely to succeed based on intuition alone; instead, it must rely on a more sophisticated, systematic approach. The basic elements of such an approach are outlined here, along with several design principles. An overview is then given of recent advances in (...) our understanding of visual perception, including rapid perception, visual attention, and scene perception. It then is argued that the mechanisms involved can be successfully harnessed to allow data to be displayed more effectively than at present. Several directions of development are discussed, including effective use of visual attention, the display of dynamic information, and the effective use of nonattentional and nonconscious perceptual systems. (shrink)

This paper examines how inner theories influence lexical choice. Subjects in one study completed auditorily presented sentence fragments, some of which contained nonhuman antecedents such as dog and cat. Subjects were more likely to use human pronouns rather than it for referring to pets rather than nonpets , and antecedents that were liked rather than disliked , familiar rather than unfamiliar , named rather than unnamed , rational rather than nonrational , and engaging in typically human rather than nonhuman activities (...) . The beliefs and attitudes underlying these pronoun choices intruded not just hypoconsciously , but contraconsciously . A second study examined rapidly generated inferences that influenced what pronoun subjects chose to complete visually presented sentences, such as "When a student practices basketball instead of studying" and "When a student practices ballet instead of studying." The results indicated that inferences from beliefs altered the choice of pronoun from predominately he to predominantly she. Other results indicated that pronouns have semi-autonomous functions of their own, and reflect beliefs and attitudes that vary with subject sex, and are context dependent, pragmatic in nature, and dynamic over time. (shrink)